SDF is making gains. Most notable is the taking of Tishrin oil fields from ISIS, which has produced in the ballpark of $100.000/day for the ISIS.
Also of note is that there was little resistance by ISIS at Tishrin, which implies strongly that despite the posturing ISIS troops are actually starting to be either quite weak, severely demoralized or both.
The formation of SDF seems to also have alleviated the problem that the otherwise effective Kurdish forces have been reluctant to advance into Sunni territory, for many obvious reasons. The new joint Kurdish/Arab forces seem to be vastly preferable to the local Sunnis in comparison to ISIS. That should make fighting ISIS much less complicated.
So as far as the ground war in Syria goes, there doesn't really seem to be much need to do anything that is not being done already. In fact things like sending in Western ground troops could actually do more harm, by revitalizing the ISIS narrative of a clash between West and Islam.
The one thing that would help though is if Turkey would stop attacking and otherwise antagonizing the Kurds. The West should really start putting some pressure on Turkey on that topic.
EDIT: Correction: obviously the SDF can only solve problems in Syria. That still leaves Iraq to be solved.